07 1098s? can i use DENSO iridium IU27 spark plug? # 5363 - Ducati Superbikes - Page 2

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07 1098s? can i use DENSO iridium IU27 spark plug? # 5363


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#21 railed

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Posted 22 August 2009 - 07:26 PM

Duatis valve guides are sh*t. The clearence is almost always out of spec by the 12k service. I have seen a handle full of 1098's that had bad guides before they even got to 15k. You will know if they go bad, Rough idle, smoke or oil spitting out of the exhaust.

And I haven't seen this on a 1098 yet, but I have seen it on other models like 2 valves
the hard coating is flaking of my cams and rockers, Specifically my closing lobes and rockers on the exhaust cam of the horizontal cylinder, and the closing lobes and rockers of the intake cam in the vertical cylinder... I didn't take pics while I was in there.

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#22 Mongo

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Posted 12 June 2010 - 11:03 AM

Put the IU27's in yesterday, and went for a test ride today - all seems good. Startup is faster, and throttle does seem crisper. That being said, my OEM's are 3yrs & 15k miles old, and look like crap. By "crap" they're just dry & black everywhere. At least they're even.

The Iridiums's were $20 for both from Amazon (includes shipping). Don't forget to gap - out of the box they had a huge gap. And don't forget about the 14mm & 16mm socket differences for OEM's vs. the Denso's. Frickin holes are so deep you can't tell.

Say Roadrunner, how did you adjust your new belts? The adjustment is my only real hesitation to doing them. That and I'm sure it'll take me a week :crash
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#23 fred900

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Posted 12 June 2010 - 11:40 AM

What did you gap them at?

#24 Mongo

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Posted 12 June 2010 - 06:39 PM

fred900 said:

What did you gap them at?

The manual says .6-.7mm, so I went with .66. Funny the old OEM's are gapped at around .92.
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#25 Shazaam!

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Posted 12 June 2010 - 09:26 PM

Regarding the use of platinum and iridium spark plugs in a Ducati:

Platinum or iridium plugs will give you worse performance than a conventional plug unless you use a larger gap than is recommended for the steel electrode plug equivalent. One by-product (and benefit) to having platinum or iridium as an electrode material is that the harder material erodes more slowly and consequently allows you to reduce the size of the center electrode and still have a long-lifetime plug. Re-gapping is infrequent or eliminated. In fact, the initial reason this type of plug was developed was an attempt to meet the 100,000-mile durability/maintenance requirement mandated by the US EPA for exhaust emissions, not because they offered any improved performance over conventional electrodes.

A smaller electrode, however, will arc at a lower voltage. This is good because the lower arc-over voltage is not as demanding on your less-than-new ignition coils and wires so the firing is more reliable. But this is also bad because a lower arc-over voltage presents a weaker spark kernel (lower arc current and duration) that is less likely to light off the air/fuel mixture.

Consequently, dyno testing shows a performance gain with specialty plugs only when their intrinsically lower arc-over voltage has allowed users to increase the plug gap above that possible with conventional steel electrode plugs. A larger plug gap needs a higher arc-over voltage to fire, and a larger gap, combined with good plug wires and coils, will span more fuel molecules resulting in a more reliable burn with fewer misfires. So you get better throttle response. Not more power mind you, better throttle response.

The transition between throttle positions involves a wide range of fuel/air mixtures and the ability to fire these less-than-ideal mixtures with a minumum of misfires is what throttle response is all about.

When it comes to spark plug gaps, bigger IS better. The larger the spark kernel that is generated by a spark jumping the electrode gap, the more likely and complete the fuel burn will be, and the smoother the engine will run. That is, the larger the spark gap that’s exposed to the air/fuel mixture, the easier it is to initiate combustion. This translates directly into improved throttle response.

Conversely, I have seen several examples of Ducati throttle response problems cured by replacing platinum/iridium plugs that were gapped too small (i.e. the 0.024 in. Ducati recommends for conventional plugs.) Both NGK and Denso pre-gap their Ducati application specialty plugs to 0.035 in. This should be considered a minimum gap for this kind of plug.

If you have a older bike, you may arc-over the plug wires before you can fire an optimized larger plug gap. If the spark plug wires have inadequate insulation, the wire cannot maintain a high enough voltage across the insulation and will arc to ground before firing the plug gap. The factory spark plug leads are stranded wire covered with an EPDM jacket and although the wire itself will last a long time, the insulating jacket will start to break down after a couple of years which is why most good aftermarket wire is insulated with silicone.

If this becomes a problem, replace the stock spark plug wires with a set of Magnecor or similar quality wires. This will allow running a larger plug gap without a concern for insulating the higher voltage needed to jump the gap. Ducati Superbike Magnecor #2549 wires, for example, run $67.

For street bikes, you should use carbon core wires, preferably carbon wires with a spiral wrap center conductor. Straight, multi-stranded, unshielded wire conductors offer theoretical gains resistance-wise, but produce lots of electromagnetic interference (EMI). One major concern is with the computer found used on fuel injected bikes since the radiated EMI can interfere with the computer and corrupt sensor and internal signals which can affect engine performance and reliability. This concern also extends to the use of non-resistor type spark plugs.

#26 Mongo

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Posted 13 June 2010 - 05:53 AM

Goddamnit. Great info Shazaam. Pretty sure the Denso's were over 1mm (.04") before I messed with them.

No way I'm taking them out anytime soon. Unless it's going to hurt something.
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#27 RRnold

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Posted 09 September 2010 - 09:35 AM

Sorry to bump up an old thread but I'm in the process of swapping out my plugs with IU27's. What is the correct gap? .92 like the oem NGK's? :dunno

#28 Mongo

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Posted 10 September 2010 - 06:28 AM

In retrospect (and due to Shazaam's article) I'd leave them like they are out of the box, after making sure both gaps are the same.
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#29 RRnold

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Posted 10 September 2010 - 09:03 AM

Shazaam! said:


Conversely, I have seen several examples of Ducati throttle response problems cured by replacing platinum/iridium plugs that were gapped too small (i.e. the 0.024 in. Ducati recommends for conventional plugs.) Both NGK and Denso pre-gap their Ducati application specialty plugs to 0.035 in. This should be considered a minimum gap for this kind of plug.


Mongo said:

In retrospect (and due to Shazaam's article) I'd leave them like they are out of the box, after making sure both gaps are the same.

Thanks Mongo. So did you re-gap your plugs or left them .66? If not, how is it running so far?

#30 Mongo

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Posted 10 September 2010 - 12:18 PM

I left them at .66 for the time being - the horiz is such a pain to take out. I'll change the gaps when I replace the fuel filter.

She's running great - after the intial quicker start-ups & throttle response (I actually think all new plugs do this) it seems normal. I'm quite intrigued to see if any long-term gains result from a larger gap, per the article. But not intrigued enough to take my frickin tank off again just for that.
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#31 RRnold

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Posted 10 September 2010 - 01:28 PM

Mongo said:

I left them at .66 for the time being - the horiz is such a pain to take out. I'll change the gaps when I replace the fuel filter.

She's running great - after the intial quicker start-ups & throttle response (I actually think all new plugs do this) it seems normal. I'm quite intrigued to see if any long-term gains result from a larger gap, per the article. But not intrigued enough to take my frickin tank off again just for that.

That's good to hear. I installed the Corse hoses and had to remove the tank, air box, throttle bodies and the entire battery box. I agree, it's a time consuming process (my first time tearing the bike apart). I'll keep the plugs at a larger gap to see how it runs.

#32 Mongo

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Posted 10 September 2010 - 08:29 PM

Cool - very interested in how it runs.
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#33 AKKutz

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Posted 11 September 2010 - 03:08 AM

I dropped mine in, left the gap as it was (hearing that the wider gap on this plug was crucial), 0 issues to date.

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#34 barryd

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Posted 11 October 2010 - 09:16 AM

There is a local shop here showing they carry the IU27 at $10.95 each. Will check it out today.
Semper Fi

#35 RRnold

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Posted 11 October 2010 - 10:01 AM

Mongo said:

Cool - very interested in how it runs.

AKKutz said:

I dropped mine in, left the gap as it was (hearing that the wider gap on this plug was crucial), 0 issues to date.

0 issues either and I can feel the difference with the new plugs; crisp throttle and runs a lot better!

#36 TTubrag

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Posted 01 August 2016 - 05:59 AM

Does anyone have long term use feedback on the Denso Iridium IU27s? Good or Bad?

Any problems crop up over time with their use (eg: prematurely deteriorating coils or leads?)

How many kilometers did they last in real world use?

Edited by TTubrag, 01 August 2016 - 05:59 AM.






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